Bonnington Water, near Leith, Scotland, 303 



This residue was dissolved in water and effervesced by the 

 addition of hydrochloric acid ; it was evaporated, the residue 

 moistened with hydrochloric acid, and after a few hours again 

 dissolved in water, when a scarcely visible sediment separated. 

 The acid fluid was supersaturated with ammonia ; oxalate of 

 ammonia gave no indication of lime, but phosphate of ammonia 

 gave a small precipitate of the ammonio-phosphate of mag- 

 nesia ; this was edulcorated upon a filter with dilute ammonia, 

 which prevents the re-solution of this salt, dried and ignited it 

 gave 0"0309gr.* of phosphate of magnesia, equivalent to 0*011 

 magnesia. Another mode of Berzelius, which gives likewise 

 very exact results, I will briefly notice. The concentrated 

 solution of the alkaline chlorides is to be evaporated to dryness 

 with oxide of mercury. The chloride of magnesium is changed 

 into magnesia, and chloride of mercury is produced, which 

 latter unites with the alkaline chlorides. The further process 

 is obvious f. 



2. Sulphuric acid. — One-twentieth part of the fluid contain- 

 ing the soluble ingredients was acidulated by hydrochloric 

 acid, and when boiling precipitated by chloride of barium. 

 The sulphate of barytes weighed 7"201 grs., which amounts 

 upon 16 ozs. troy to 14''403 grs., equivalent to 4'950 grs. of sul- 

 phuric acid. If we compare this result with the one obtained 

 by the preliminary experiments at 1, it will be seen that it 

 closely agrees. 



3. Nitric acid. — 810 grs. of the fluid containing the so- 

 luble ingredients were very carefully neutralized by dilute 

 sulphuric acid and macerated with a due proportion of sul- 

 phate of silver, in order to change the chlorides, iodides and 

 bromides into sulphates J. The fluid separated from the 

 silver precipitate was made alkaline by a little carbonate of 

 soda, concentrated in a water-bath to a few ounces, and 

 mixed in a tubulated retort with an adequate quantity of che- 

 mically pure sulphuric acid (previously boiled), more than 

 sufficient to convert all the ingredients into bisulphates. This 

 mixture was heated in a sand-bath and the vapours con- 

 ducted into a glass receiver containing a solution of hydrate 

 of barytes, and the distillation interrupted as soon as fumes 



* I have to notice that I used the French gramme for ascertaining the 

 weiglit of the ingredients, which I applied with precision to the first decimal 

 number of a millcgramme. 



t See Berzelius's Ja/iresimc/i^. 21st Jahrgang, 2nd Theil. 



X A fluid containing a large amount of chlorides would require a very 

 considerable quantity of the solution of sulphate of silver, inasmuch as this 

 salt requires a great deal of water for its solution. To avoid this it is only 

 necessary to mix the diluted fluid with the sulphate of silver, which has been 

 previously triturated in a mortar with water, and to leave it for some time 

 in a temperature not exceeding 100° F. 



